Flat-slab floor.



c. A, P.. TURNER. FLAT SLAB FLOOR.

APPLICATION FILED APR. 20,1915- Patented Feb. 27, 1917.

SECTION A A SEC 770 -5-5 a I INVENTOR 1 v I Q rinrrs n STATES PATENT names,

I CLAUDE A, P. TURNER, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO C. A. P. TURNER COMPANY, A CORPORATION OF SOUTH DAKOTA.

FLAT-SLAB FLOOR.

1 Specification of Letters Patent.

Patented Feb. 2?, 1.917.

Application filed April 20. 1915. Serial No. 22,623.

To all whom it may concern:

Be it known that I, CLAUDE A. P. TUB- Hennepin, and in the State of Minnesota,:

have invented 'a certain new and useful Improvement in Flat-Slab Floors. and do hereby declare that the following is a full, clear, and exact description thereof.

My invention relates to flat plate, columnsupported members of building and other structures of concrete so reinforced as to imitate the action of a flat plate of homogeneous material, Plate action insuch a member-a floor for example-is brought about by bond shear resistance. that is the resistance to horizontal shear between the reinforcing rods, ruining in intersecting directions, and the concrete matrix, which resultsin the generation of lines of force corresponding to compressions and tensions inthe concrete at forty-five degrees to the rods, the. lines of force from one rod being neutralized by opposing lines of force from an adjacent intersecting rod. Bond shear resistance is greatest where the increment of moment is greatest and is zero where the momentpasses through a maximum. The especial object of my invention is to place the reinforcing metal in those portions of the slab where theaction of bond shear is intensified, and in the'zones or regions of greatest indirect stress, and thereby most efficiently to utilize the metal.

In the accompanying drawings Figure 1 IS a top plan view of the reincenter, suchrods being carried toward the bottom of the slab between columns, and toward the top of theslab over the columns so that they lie in the tension zones. At the columns the rods 12 rest upon supporting frames of manifoldcd or back and forth bent rods 14 in groups at right angles, having a cruciform arrangement, supplemented, if desired by a concentrically disposed spi *al rod 15 that rests on said frame in the tension zone and over which the belts of rods 12 cross, thus providing the necessary metal for taking shear at the columns, and for producing' the circumferential cantaliver action about the columns.

Bond shear action is a maximum about the circumferei'ice of the suspended central portion of the slab, and for that reason I run belts of parallel rods 16 obliquely between mid-span of one direct belt of rods 12 and the belt of rods 12 at right angles thereto, or parallel with the diagonals of the rectangle; but, obviously, without crossing the col-- umns, and this results in forming rectangles that are respectively concentric with a column and with the suspended central portion of the slab, with the result that the ac tion of bond shear is intensified where it is highly useful, and that the metal is con centrated at mid-span of the lines directly between columns, or at the zone of greatest stress in such lines. By mid-span, as will be evident, I mean that portion of the span on the direct line from one column to another which liesbetween two adjacent columns on such direct line, and it will be seen that a belt of obliquely extending rods 13 thus reaches from one bay, or panel at midspan continuously across an adjacent bay, or panel at the corresponding point.

Parallel with the direct belts of rods, I place more widely spaced parallel suspension rods 17, that, thus running in two directions intersect at the suspended central portion. of the slab, dipping toward the bottom of such portion and rising toward the top of the slab on the direct lines between columns, where they are carried over a supporting rod 18, and thus provide the reinforcement necessary in that area of the slab at the central part thereof inclosed by the rectangle formed by the groups, or belts of oblique rods 16.

My invention is applicable to those cases where the slab at one or more sides reaches to and rests-"upon a beam or Wall.

Having thus described my invention what I claim is 1. A column-supported slab of concrete, having at the columns circumferential cantaliverf elements and having slab reinforcement that includes obliquely extending belts other that cross each oth r at points between the columns, and extended across sieve al adjacent panels crossin from one panel to ana points oi ,stantially at mid-span of the 1 el on direct lines between colan angle to each other.

between c an, said areas being crossed by other rorceinenl;

i; l f v 0. i coluinn-supported slab ol concrete, ha ring at the columns c1reuiniereninil canlalivei' elements and baring; slab rcin'l orce meat that includes obliquely extending;- belts that cross each othe' at points between the columns, and extended across several adja cent panels crossing from one panel to anotl at points subslantiall at mid-span of the panel on direct lines between columns in lines at an angle to each other, and belts that extend from column in column.

l. rolluiursupporteo slab o l concrete liiiVliif al; rcini oreei Hi Q t l L includes ob iajl cross each other ween the columns, and extended al =5 nels cr ssing 'lloni I it suhstantially eci; lines he- 1 1 ll illlgiil ii) QllCll other, belts of rods that extend from column to column and cross each other thereat, and belts of rods that extend at. right, angles thereto and to each other that extend lJGtWGkll points between the columns, the re iiii'orcenient al; the columns being in the tension zone, and forming therat with the concrete :1 circunrferenlial cantaliver.

5. A colulna-supported slab of concrete, having slab reinforcement that includes oi,- liquely extending belts that cross each other at points between the columns, and extended across several adjacent; panels crossing from one panel. toanother :it points sulistantiall at niid-span of the panel on direct lines hetwern columns in lines atan angle to each other, and bells that extend from column to column, and spiral rods all the columns, the reinforcenicnt at the columns being in the tension zone,'and forming thereat with the concrct a circumferential antaliver.

(3, A colunnrsupportcd slab of concrete, having slab rein'ljorceinent that includes obliquely extending belts that cross each other at points between the colinnns, and extended across several adjacent panels crossing from one panel to another at points substantially at iniilspan of the panel on direct lines between columns in lines at an angle to each 

